Merge tag 'topic/drm-misc-2015-07-28' into drm-intel-next-queued

We need a few core drm patches to be able to merge Maarten's series to
convert DPMS over to atomic.

Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>

1 files changed, 13 insertions, 0 deletions

diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 1c2bd1723e40..171312d51799 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -2296,9 +2296,22 @@ static int run_one_delayed_ref(struct btrfs_trans_handle *trans,
 static inline struct btrfs_delayed_ref_node *
 select_delayed_ref(struct btrfs_delayed_ref_head *head)
 {
+	struct btrfs_delayed_ref_node *ref;
+
 	if (list_empty(&head->ref_list))
 		return NULL;
 
+	/*
+	 * Select a delayed ref of type BTRFS_ADD_DELAYED_REF first.
+	 * This is to prevent a ref count from going down to zero, which deletes
+	 * the extent item from the extent tree, when there still are references
+	 * to add, which would fail because they would not find the extent item.
+	 */
+	list_for_each_entry(ref, &head->ref_list, list) {
+		if (ref->action == BTRFS_ADD_DELAYED_REF)
+			return ref;
+	}
+
 	return list_entry(head->ref_list.next, struct btrfs_delayed_ref_node,
 			  list);
 }